to get one of every single obtainable (as in, not the old promos, winter crates, proof of purchase, primeval warrior badge, charity bundle hats, etc) hat and misc in every quality (excluding unusual) that it comes in?

How much more would it take to purchase every weapon in strange/vintage/genuine quality?

This is assuming that $5 = 3 keys = 7 ref 2 rec.

Any random guesstimates? Would anyone even be bothered to figure it all out?

This is purely hypothetical, of course.

EDIT: Why not tack in one of each tool/paint while we're at it. Just for fun.

Every item, every quality? A lot. Consider the Vintage Shortstop, probably only one in the world. I bet if you offered 800 keys for it you would be turned down. Vintage Companion Cube Pin... 400 keys+, Vintage Max Head... 1400 keys+.